Method and means for dressing internal grinding wheels



Sept. 3, 1963 G. E. ULUE 3,102,529

METHOD AND MEANS FOR DRESSING INTERNAL GRINDING WHEELS Filed July 3, 1961 4 Sheets-Sheet 1 INVENTOR. afddfi viz/v4.

Sept. 3, 1963 G. E. LlLLlE 3,102,529

METHOD AND MEANS FOR DRESSING INTERNAL GRINDING WHEELS Filed July 5, 1961 4 Sheets-Sheet 2 M56 0 7 Wheel 512/? 62/149? ZZZIZZZIQ,

mf /z lmm Sept. 3, 1963 G. E. LILLIE 3,102,529

METHOD AND MEANS FOR DRESSING INTERNAL GRINDING WHEELS Filed July 3, 1961 4 Sheets-Sheet 3 INVENTOR. 62/14? E 452712,

BY '%%*MW,%% V m p 3, 1963 G. E. LlLLlE 3,102,529

METHbD AND MEANS FOR DRESSING INTERNAL GRINDING WHEELS Filed July 3, 1961 4 Sheets-Sheet 4 INVENTOR. 607/077 ,5? 47272-5 United States Patent O 3,102,529 METHOD AND MEANS FOR DRESSING INTERNAL GREJDING WHEELS Gordon E. Lillie, Bellows Falls, Vt., assignor to Bryant Chucking Grinder Company, Springfield, Vt., a corporation of Vermont Filed July 3, 1961, Eer. No. 121,565 26 Claims. (Cl. 125-11.)

This invention relates to grinding, and more particularly to a method and means for dressing internal grinding wheels in order to achieve uniform dimensional accuracy in the bores of small parts. This application is a continuation-in-part of application Serial No. 19,559, filed April 4, 1960, now abandoned, by, the present applicant.

Size reliability in internal grinding of small parts on a production basis is dependent to a large extent on the uniformity with which the grinding wheel is dressed. The grinding wheel dressing action is especially important with a new wheel, since these vary in diameter and may be out of round. Besides insuring that each new grinding wheel is dressed to a predetermined size, the rate of wheel traverse and amount of in-feed with respect to the diamond must also be closely controlled, since otherwise the cutting ability of the wheel may vary, affecting the size of the first workpiece ground, and possibly reducing diamond life.

It is furthermore essential for reliable small part internal grinding that each succeeding dress of the grinding wheel be uniform, so that a proper relationship will be maintained between the position of the grinding wheel, before grinding, and the diameter of the finished ground hole. Any variation in the amount of wheel material removed by dressing has an important effect on this relationship, especially in holes of small diameter and rela tively great depth, since the cantilever support for the grinding wheel spindle can result in substantial wheel deflection.

It is an object of the present invention to provide a novel method and means for insuring grinding wheel dressuniformity both for new wheels and for the re-dressing of wheels between workpieces.

It is another object to provide an improved method and means for automatically dressing a new wheel repeatedly in a uniform manner until the new wheel is dressed to a predetermined size. In this connection, it is an object to provide means for sensing that the next auto matic dress cycle will result in the predetermined size, to terminate dressing the new wheel at the end of this cycle, and to initiate automatically repeated workpiece grinding cycles.

'Other objects, features and advantages of the present invention will become apparent from the subsequent description, taken in conjunction with the acocmpanying drawings.

In the drawings:

FIGURE 1 is a schematic plan sectional view of a typical grinding wheel unit of an internal grinder incorporating the features of the invention;

FIGURE 2 is a side elevational view of the schematic unit of FIGURE 1, partly sectioned;

FIGURE 3 is a wiring diagram illustrating electrical control means for carrying out the invention;

FIGURE 4 is a chart of the sequence of events in carrying out the invention; and

FIGURE 5 is a schematic plan view of a portion of another embodiment of the invention in which a contoured grinding wheel is to be dressed, the diamond oscillating with respect to the wheel when the latter is in dressing position.

In general terms, the illustrated embodiment of the int 2 vention comprises a grinding wheel spindle support capable of traversing movement in the direction of the spindle axis and feed movement transverse to this axis, together with a dressing diamond adapted to be moved between retracted and dressing positions.

Means are provided for automatically controlling the movement of the grinding wheel spindle and dressing diamond in such manner that, with a new grinding wheel mounted on the spindle, the grinding wheel will traverse clear of the retracted diamond, the wheel traverse then being reversed and the wheel fed toward the diamond a predetermined amount. The diamond is moved to its dressing position and the wheel and diamond move relative to each other, thus dressing the wheel, the diamond then being retracted. This cycle, referred to as cycle A, is repeated automatically until the wheel has been so positioned that one more pass of the diamond and wheel relative to each other will dress the wheel to a predetermined size.

As the grinding wheel approaches the desired size, a cycle B occurs, this cycle being identical with cycle A except that during cycle 3 a limit switch senses that the next wheel dress is the last dress required to dress the wheel to a predetermined size. Cycle B setsup the initiation of cycle C, which occurs at the end of cycle B and consists of traverse movement of the griding wheel into the unfinished workpiece bore, feed movement of the grinding wheel to finish the workpiece, backing oif of the wheel and reversal of the wheel slide, movement of the diamond to its dressing position as the wheel and diamond move relative to each other to dress the wheel, retraction of the diamond, operation of a loader to replace the finished workpiece withan unfinished workpiece, cocking of the back-off mechanism and dressing compensator, and reversal of the slide so as to traverse toward the new workpiece. Cycle C may be repeated for as many workpieces as can be ground with the wheel.

Referring more particularly to the drawings, FIG- URES 1 and 2 show in schematic fashion a grinding wheel 11 the spindle of which is mounted in a traverse slide 12 adapted to travel a distance 13 between positions 14 and 15-. Slide 12 is mounted in a cross slide 16 carried by a stationary housing 17 and engaging the housing by means of extensions 18. A feed housing 19 is attached to housing 17, and a feed screw 21 is disposed within housing 19 and is threadably engaged by a feed nut 22 rotatably mounted in housing 19 and held against axial movement, nut 22 including one-way clutch means (not shown). A stationarily mounted cylinder 23 has a piston 24 connected by an arm 25 to nut 22. Arm 25 is movable between a stop 26, when piston 24 is extended, and a stop 27, as seen in FIGURE 2, the arm being movable against stop 27 by a spring 28 when cylinder 23 is ex hausted. Movement against stop 26 will cock arm 25 without rotating nut 22, and movement of arm 25 against stop 27 will rotate nut 22, causing. screw 21 to advance in the direction of the arrow 29 in FIGURE 1, thus feeding grinding Wheel 11 toward the diamond a predetermined amount and presenting wheel material to be dressed off by the diamond. The diamond is shown schematically at 31 and is movable between a retracted position shown in solid lines and a dressing position shown in dotted lines. A suitable drive shown schematically at 32 is connected to the outer end 33 of feed screw 21 for advancing the wheel in direction 29 and into the bore surface 34 of a workpiece 35 for removal of workpiece material by grinding. Rotation of the feed screw for this feed movement is indicated by the arrow 36. Rotation of the feed screw in the direction of the arrow 37, by drive 32, permits the force of a spring 38 to move slide 12 and wheel ,11 in the direction indicated by the arrow 39, this being called back-off motion. The feed motion in the direction ent application.

back-off motion is limited by a feed stop 42, these stops being disposed within housing 19 and engageable by a shoulder 43 on screw 21. A construction of this general nature is shown and described in my copending application, Serial No. 843,710 filed October 1, 1959, now Patent No. 3,043,062, and assigned-to the assignee of the'pres- The dress compensating and grinding feed arrangements shown schematically in this application could be constructed in accordance with the said copending application within the principles of the invention.

The traverse motion of slide 12 may be accomplished by a hydraulic cylinder 44 having a chamber 45 which when pressurized, will move the slide to the left and when exhausted will permit a spring 46 to return the slide. A limit switch LS1 adjacent slide '12 is movable by a member 47 carried by the slide between a position A (when wheel 11 is at position 28 just short of position 14-) and a position B when wheel 11 reaches a position 49 just short of position15, that is, when it is almost fully within workpiece 35. Another limit switch LS2 is actuated at either extreme limit of traverse by a member 51 carried by slide 12, .that is, when the wheel reaches positions 14 or 1 5. More particularly, LS2 is moved to position A when the wheel reaches position 14 and is moved to position B when the wheel reaches position 15. A third limit switch LS3 is movable by a member 52, carried by the slide, from a position A when wheel 11 is to the right of a position 53 or to the left of a position 54, to a position B when the wheel is between these two positions. Positions 53 and 5'4 are on opposite sides of dressing diamond 3 1, the wheel when moving from position 54 to position 53 being dressed during operation.

The electrical controls for carrying out the various cycles may perhaps best be described with respect to FIGURES 3 and 4. The electrical diagram of FIGURE 3 shows all relays in their de-energized position, and to the right of the diagram is a chart which will aid in locating the switches associated with each relay. Each vertical line represents a control relay, and the dots on that line are at the levels of the various switches which the relay operates.

. M 1, which may be a hydraulic pump motor relay, the work motor relay, the wheel motor relay, and CR1 are energized to start the machine by pressing the associated start buttons 55 and 56. Energy flows to energize each relay, the relays in turn operating holding switches to maintain the relays energized after the start buttons are released.

Of the various relays, it may be mentioned at this time that control relays CR9, CR5, CR6 and CR7 are associated with the new wheel dress cycle, that is, cycles A and B. Control relay CR2 is associated with either the new wheel dress cycle or grinding cycle C, while control relay CR3 is associated only with the grinding cycle. FIGURE 4 shows the sequence of events and indicates the positions of the various limit switches, contact relays and solenoid valves for cycles A, B and C. As mentioned previously, cycle A automatically and repeatedly dresses the new wheel, cycle B is similar to cycle A except that a dress finish sensing switch '57 is actuated, the cycle C immediately follows cycle B, grinding one workpiece automatically and being repeated for as many workpieces as can be ground with the wheel.

Energizing M1 and CR1 closes normally open switches M1-1, M1-2, CR11 and CR1-2 permitting current to flow along the left-hand conductor 58 of FIGURE 3. Pressing new wheel dress button 59 permits current to flow through LS2 which is in position A (wheel 11 being at position 14-), switch 57 in position B, through conductor 61, push-button switch 59' and CR9 to energize this relay. Energizing CR5 will close holding switch CR9-1 and also closes switch CR92 which permits current flow to CR2 and SVd through normally closed 4 switches CR6 1 and CR3-1. Energization of 8V4 will pressurize cylinder 23, swinging arm 25 against stop 26 to cook the dressing compensator. Energizing CR2 will close switch (IRE-1, thus energizing solenoid valve Energizing SVZ will cause slide 12 to traverse to the left in FIGURE 1 from pos-tiion 14- toward position 53. As the slide reaches position 53, it will actuate LS8 from position A to position B. Current will flow through CR9-3, LS8, CR9-4, CR62 and CR7-1 to CR5. Ener gizat-ion of CR5 will close switches CR5-1 and CRS-Z in preparation for the later energization of CR6. As slide 12 continues to travel wheel 11 will reach position 54, actuating LS8 from B to A. Current will flow through LS8 and CR52 to CR6. Energization of CR6 will close a holding switch CR6-3 and CR64 in the circuit of CR7,

and will open CRti-l in the circuit of CR2 and 8V4;

25 to rotate arm 25 and nut 22 until arm 25 engages stop 2'7. This will cause advancement of wheel 11 in the direction of the arrow 29 a predetermined distance preparatory to dressing. De-energization of CR2 will open switch CR2-1 in the circuit of 5V2. This will cause slide 12 to reverse its direction and travel from'position 54 toward position 53-.

I LS8 will thus be actuated from A to B by member 52. Current will flow through LS8, CR9-4 and CR6-4 to CR7, and also through switch CR95 to 8V3.

Energizing SV3 will cause diamond 301 to move from its retracted position toward its dressing position, shown in dot-dash lines in FIGURE 1. Since the wheel had been previously fed in the direction of the arrow 29, traverse of wheel 11 from position 54 to position 53' will permit the diamond to dress material from the wheel.

Energizing CR7 will close switch CR7-2 and open CR7-1, tie-energizing CR5. It will be noted that CR7 functions to de-energize CR5, the latter control relay affecting the CR6 circuit. As wheel 11 reaches position 53, LS8 will be actuated from B to A. There will be no current flow since (IRS-2 is open. Current flow to 8V3, CR6 and CR7 will also cease, it being noted that normally closed switch CR97 between position B of LS8 and 8V8 and 8V3 is open. No current will flow to CR6 because CR5-1 is open. De-energization of SV3 will cause retraction of diamond 31, while the de-energization of CR6 and CR7 will restore the condition of all the control relays existing before the first event of cycle A.

As noted previously, repetition of cycle A will con tinue until wheel 11 moves to a position in which the next dress would dress the wheel to a predetermined size. This position is sensed by the dress finish sensing switch 57 in the circuit of CR2. This switch may be associated with adjustable means (not shown) for pre-selecting the position of the spindle axis relative to diamond 31 (measured transverse to the spindle axis) at which switch 57 is actuated. When this occurs, during that portion of a cycle De-energization of CR6 at the end of cycle B (because i of shifting of LS8 to position A, as previously described with respect to cycle A) will close a circuit from line 5'8 through LS2 (in position A) switch 57, CRG-l and CR3-+1 to CR2, and 8V4. Energizing 8V4 will cock the compensator, and energizing CR2 will close a circuit to 'SVZ, through CR2- 1. This will reverse the slide, oausing wheel traverse from right to left in FIGURE 1, from position 53 to position 54. LS8 will be iaotuated twice, that is, from position A to position B and back to posi tion A with no effect.

The reason movement of LS8 has no effect after th end of cycle B is because CR9 has been tie-energized at the end of cycle B by de-energization of CR6, since this opened CR65. It is therefore seen that CR6 also functions, through its de-energization, to initiate cycle C. One difference in cycle C from cycles A and B is that movement of LS8 has no eiiect at the beginning of cycle C, so that the Wheel can move past position 54 toward position 49. As slide 12 reaches position 49 it will actuate LS1 from position A to position 13. The slide will continue until position 15 is reached where it will actuate LS2 from position A to position B. This will permit current to flow from line 5% through LS2 in position B and CR3-2 to feed motor relay FMR. Energization of FMR will cause actuation of drive 32 in FIGURE 1, rotating feed screw 21 in direction 36 to feed grinding wheel 11 into surface 34 of workpiece 35. When the grinding wheel has reached the proper depth, for the desired bore size, feed'stop switch 62 (which could actually be combined with a mechanical stop as described in the aforementioned co pending application) will be actuated to its closed position. This will cause current to flow to 3V6 through lines 58 and 63, LS2 (in position B), line 64- and switch 62.

Solenoid valve 8V6 when energized will reverse drive 32, causing feed screw 21 to rotate in the direction of arrow 3'7, and the grinding wheel will thus be backed off or withdrawn from the workpiece surface a predetermined amount. Current will also flow to CR3, bypassing open switch CR3-3 through line 65, energization of CR3 closing switch CR33 and opening switch CR3-2. Switch CR3-3 will hold CR3 in its energized position, and opening of switch CRS-Z will dc-energize FMR.

Energization of CR3 will also open CR31 in the circuits of CR2 and 8V4. De-energization of SV4 will cause depressurizing of cylinder 23, rotating nut 22 to advance screw 21 in the direction of arrow 29, as described with respect to cycle A. De-energization of CR2 will open switch CR2-1 in the circuit of 5V2, and de-energizing of SVZ will cause slide 12 to reverse its direction and travel from position 15 toward position 54.

As slide 12 reaches position 54, LS8 will be actuated from position A to position B, causing diamond 31 to advance to its dressing position by energization of SV3, current flowing from line 58, through line 63 to LS2 in position B, normally closed switch CR9-6, LS8 in position B, and normally closed switch CBS-7 to SVS. As the wheel traverses the diamond it will be dressed, the slide then actuating LS8 from position B to position A. 8V3 will be de-energized and the diamond will return to its retracted position.

Unlike cycle A, the slide will continue past position 53 to position 48 because of the de-energized position of CR9. There it will actuate LS1 :from position B to position A. This will permit current flow from line 53 through line 63, LS2 in position B, line 64 and LS1 to SVS. Energization of 8V5 will operate a loader, shown schematically at 66 in FIGURE 1, this loader serving to discharge the ground workpiece 35 and feed a new workpiece [into grinding position.

Slide 12 will continue until it reaches position 14, where it will actuate LS2 from position B to position A. This will dc-energize 8V6, SV5 and CR3. De-energization of 3V6 will cook the feed back-cit solenoid valve, and dcene-rgization of CR3 and 8V5 will result in all limit switches, control relays and solenoid valves being returned to the conditions existing at the start of cycle C. Cycle C will therefore repeat itself. A worn wheel switch and sensing mechanism (not shown) could be provided to stop the grinding and signal the need for a new wheel when repeated compensation and wheel dressing has reduced 1 the wheel to a minimum usable size.

in its dressing position.

tion is different (from the preceding embodiment in that the dressing of the grinding wheel is accomplished by oscillating the diamond in its dressing position on an arcuate path so as to create a contoured grinding wheel surface for use in grinding internal bearing raceways or the like. The other portions of the system are similar to those described with respect to the embodiment of FIGURES 1 to 4. Like the previous embodiment, the grinding Wheel is dressed by advancing the spindle toward the diamond and moving the wheel and the diamond relative to each other to dress the wheel. In the previous embodiment the relative dressing movement between the wheel and diamond was accomplished by traversing the Wheel past the diamond. Here, the relative movement is accomplished by oscillating the diamond around the periphery of the wheel.

FIGURE 5 shows in schematic fashion a grinding wheel 101 the "spindle of which is mounted in a traverse slide 102 adapted to travel a distance 103 between positions 104 and 105. Slide 102 is mounted in a cross slide 1% carried by a stationary housing 197 and engaging the housing by means of extensions 108. The feed means (not shown) are similar to those shown in FIGURE 1. When in position 1114, wheel 101 is adapted to be fed toward the internal surface 109 of a workpiece 111. Surface 109, which may be a bearing raceway, has a concave iarcu ate cross-sectional shape, and the outer portion of grinding wheel 151 has a convex arcuate cross-sectional shape complemen-tary to that to be produced on internal surface 109.

A diamond shown schematically at 112 is provided, this diamond being movable between a retracted position shown in solid lines and a dressing position. 'In its dressing position, diamond 112 is oscillatable on an arcuate path between extreme positions shown by dot-dash lines and double dot-dash lines in FIGURE 5. The center of osciilation is a point indicated at 113 which coincides with the center of curvature of the are forming the crosssectional shape of the outer portion of wheel 101. Point 113 is located at dressing position of wheel 101, and may be referred to as the dressing position of diamond 112, since the diamond oscillates about this point when Means in the form of limit switches indicated schematically at 114 and 115 in FIG- URE 5 serve to cause oscillation of diamond 112 between its extreme positions when the diamond is in its dressing position. The retracted position of diamond 112 may not be in the same plane as the movement of the diamond when in its dressing position, but is shown in the same plane in FIGURE 5 to facilitate the description.

In operation of the embodiment of FIGURE 5, initiation of the cycle will cause diamond 112 to move from its retracted position to one extreme of its dressing position as shown in dot-dashlines in FIGURE 5. When it reaches this position, the dress compensating mechanism will be cocked as in the previous embodiment, and the diamond will sweep around center 113 to its other extreme dressing position, as shown in double dot-dash lines in FIGURE 5.

This will actuate switch 115, causing the diamond to reverse its movement toward its dot-dash position in which it will actuate switch 114. Wheel 101 will be fed by the compensating mechanism in the direction of arrow 116 in FIGURE 5, and diamond 112 will again oscillate between its extreme dressing positions. The compensator cocking, diamond sweep and wheel compensating movements will continue until the axis of wheel 101 has reached a first predetermined distance from the dressing position of dia mond 112.

After Wheel 1011 has been dressed following the cornpensating movement during which the wheel axis has reached the first predetermined distance from the diamond dressing position, the diamond will move to its retracted position and slide 102 will move to the left in 7 FIGURE until it has enteredworkpiece 111, during which time the compensator will he cocked again. The cross slide 106 will then he ied upwardly in FIGURE 5 by the feed motor, grinding wheel llil engaging internal workpiece surface 169. When the feed limit switch has been actuated, the cross slide will be hacked oil until the feed motor stops and slide 102 will then he moved to the right.

Another compensating movement of grinding wheel lill will take place, a loader will he operated to replace the finished workpiece with an unfinished workpiece, and diamond 112. will move from its retracted position to its dressing position. Wheel 1M will stop in its dressing position 105 and the diamond will oscillate hack and forth around center 113. The compensator will again be cocked, and after the diamond has moved through its dressing sweep movement, another compensating movement of the wheel will take place, after which the. diamond will again sweep through its dressing movement. The diamond will then move to its retracted position and the back-off mechanism will be cocked.

While it will be apparent that the preferred embodi- I ments of the invention disclosed are well calculated to fulfil-l the objects above stated, it will he appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoinedclaims.

What is claimed is:

1. In a method for diamond dressing a new grinding wheel preparatory to grinding a workpiece hone to a predetermined diameter, thes-teps of providing a dressing position for the diamond which is a predetermined distance from the final bore diameter in a direction transverse to the spindle axis, dressing a new grinding wheel mounted on said spindle by advancing the spindle toward the diamond and traversing the wheel past the diamond in the direction of the spindle taxis, repeating the dressing steps until the spindle axis has advanced to within a first predetermined distance of the diamond measured in a direction transverse to the spindle axis, traversing the grinding wheel into grinding position within the workpiece bore, feeding the grinding wheel and spindle toward the bore surface, and stopping said feed movement when the spindle axis has arrived at a second predetermined distance from :said diamond less than said first predetermined distance. i

2. In a method for diamond dressing 2. new grinding wheel preparatory to grinding a workpiece bore to a predetermined diameter, the steps of providing a diamond dressing position which is a predetermined distance from the final bore diameter measured in a direction transverse to the spindle axis,positioning a new spindle-mounted grinding wheel on one side of the diamond when regarded in the direction of the spindle axis, feeding the grinding wheel a predetermined dress compensating distance toward the diamond in a direction transverse to the spindle axis, traversing the grinding wheel past the diamond to dress the wheel, reversing the wheel tnaverse to its original position, again feeding the wheel toward the diamond the same predetermined distance and traversing the wheel past the diamond to again dress the wheel, repeating the feeding and dressing steps until the spindle axis and advanced to a first predetermined distance from the diamond, traversing the wheel into the workpiece bore, and feeding the wheel into the bore surface until the spindle axis is a second predetermined distance from the diamond less than said first predetermined distance.

3. The method according to claim 2, further including .the steps of backing off said wheel from the finished bore surface, feeding the wheel said predetermined dress compensating distance toward the diamond to compensate feeding the wheel into the bore surface of the new workpiece until a third predetermined distance is reached.

4. In a method for diamond dressing a new grinding wheel preparatory to grinding a work-piece bore to a predetermined diameter, the steps of providing a diamond dressing position which is a predetermined distance from the final 'bore diameter measured in a direction traverse to the spindle axis, positioning a new spindle-mounted grinding wheel on one side of the diamond when regarded in the direction of the spindle axis, feeding the grinding wheel a predetermined dress compensating distance to ward the diamond in a direction transverse to the spindle axis, traversing the grinding wheel past the diamond to dress the whtel, reversing the wheel traverse to its original position, again feeding the wheel toward the diamond the same predetermined distance and traversing the wheel past the diamond to again dress the wheel, moving the diamond \from its dressing position to a retracted position each time the wheel returns to its original position and returning the diamond to its dressing position as the wheel again traverses past the diamond for another dressing operation, repeating the feeding and dressing steps until thespind-le axis has advanced to a first predetermined distance from the diamond, traversing the wheel into the workpiece bore, and feeding the wheel into the bore surface until the spindle axis is a second predetermined distance from the diamond less than said first predetermined distance.

5. The method according to claim 4, in which the original position of the wheel is between the diamond and the workpiece regarded in the direction of the spindle axis, the dressing traverse of the wheel lacing in a direction away from the workpiece.

6. In combination with an internal grinding wheel spindle having a traverse slide and cross slide, a diamond movable in a direction transverse to the spindle axis be tween retracted and dressing positions, a workpiece station at one side of said diamond, the diamond dressing position being a predetermined distance from the final workpiece hore diameter in a direction transverse to the spindle axis, means for repeatedly and sequentially feeding the grinding wheel toward the diamond, moving the diamond to dressing position and traversing the grinding wheel past the diamond to dress the wheel, means for sensing the arrival of the spindle axis at a first predetermined distance flOlTl the diamond dressing position, and grinding cycle initiating means responsive to actuation of said sensing means to terminate said repeated (feed, traverse and dressing movements.

7. The combination according to claim 6, said sensing means being actuatable by the final feeding movement of said grinding wheel toward the diamond but before the final dressing traverse of the wheel, and means for causing said grinding cycle initiating means to he ineffective until said final dressing traverse has been completed.

8. The combination according to claim 6, said grinding cycle initiating means including means for causing the grinding wheel to traverse into the workpiece bore, means responsive to arrival of the grinding wheel in the workpiece bore for feeding the grinding wheel into the bore surface, and means responsive to arrival of the spindle axis at a second predetermined distance from said diamond dressing position for halting said feed movement. I

9. The combination according to claim 8, further provided with means responsive to arrival of the spindle axis at said second predetermined distance for backing off said grinding wheel from the bore surface, feeding said grinding wheel a predetermined dress compensating distance toward the diamond dressing position to compensate for grinding wheel wear, and causing traverse of the grinding wheel past the diamond, and means responsive to approach of said grinding wheel to the diamond for moving the diamond to its dressing position against the wheel.

10. The combination according to claim 9, further pro vided with means responsive to completion of said lastmentioned traverse movement of the grinding wheel for reversing the grinding wheel movement and traversing the grinding wheel toward the workpiece station.

11. In combination with an internal grinding wheel spindle having a traverse slide for movement toward and away from a work station and a cross slide, means for traversing the grinding wheel spindle from a start position toward said work station, means for stopping said traverse movement at a predetermined finish position with the grinding wheel within the workpiece bore, a dressing diamond located between the start and finish positions of said grinding wheel during said traverse movement, means for feeding said grinding wheel irrto the bore surface until the grinding wheel spindle axis is a predetermined distance from said diamond dressing position, means responsive to arrival of said grinding wheel at said last-mentioned position for stopping the grinding wheel feed movement, backing off the grinding wheel from the workpiece, feeding the grinding wheel a predetermined dress compensating distance from its backedolf position toward the diamond in a direction transverse to the spindle axis, and traversing the grinding wheel past the diamond to dress the grinding wheel, and means responsive to arrival of said grinding wheel at a predetermined position on the other side of said diamond for reversing the grinding wheel traverse and traversing the wheel toward the workpiece station.

r 12. In combination, an internal grinding wheel having first and second extreme traverse positions and first and second intermediate traverse positions, a workpiece station at said second extreme traverse position, a dressing diamond between 'said two intermediate traverse positions, means for traversing said wheel from said first traverse position past said first intermediate position to said second intermediate position, means responsive to arrival of said wheel at said second intermediate position for feeding said wheel a predetermined dress compensating distance toward said diamond in a direction transverse to the grinding wheel axis and stopping and reversing the direction of grinding wheel traverse, means responsive to reversal of said grinding wheel traverse direction for moving said diamond from a retracted position to a dressing position, said dressing position being a predetermined distance from the workpiece bore finish diameter measured in a direction transverse to the grinding wheel axis, means responsive to arrival of said grinding wheel at its first intermediate position from its second intermediate position for moving said diamond to its retracted position and again reversing the direction of grinding wheel traverse, means responsive to rearrival of said grinding wheel at said second intermediate position for again feeding said grinding wheel said predetermined distance toward the diamond, and means responsive to arrival of the grinding Wheel axis at a predetermined distance from said diamond dressing position for disenabling the means for stopping and reversing said grinding wheel traverse at said second intermediate position when moving from said first intermediate position.

13. The combination according to claim 12, further provided with means responsive to movement of said grinding wheel from its first intermediate position past its second intermediate position to said second extreme position for stopping said grinding wheel and feeding the grinding wheel into the workpiece surface, and means responsive to arrival of the grinding wheel axis at a second predetermined distance from said diamond dressing position less than said first predetermined distance for backing off and stopping said feed, feeding said grinding wheel toward the diamond said predetermined dress compensating distance, and reversing the direction of slide traverse.

14. The combination according to claim 13, further provided with means responsive to movement of said grinding wheel from said second extreme position to said second intermediate position for moving said diamond from its retracted to its dressing position and responsive to the arrival of the grinding wheel at its first intermediate position for retracting the diamond.

15. The combination according to claim 14, further provided with means responsive to movement of the grinding wheel from its first intermediate position to a position adjacent said first extreme position for replacing the finished workpiece with an unfinished workpiece at the workpiece station, and means responsive to arrival of the grinding wheel at said first extreme position for reversing the traverse direction of said grinding wheel.

16. In a system for the sequential control of an internal grinding wheel and diamond dresser, a grinding wheel spindle having first and second extreme positions and first and second intermediate positions, a workpiece station at said second extreme position, a diamond dresser between said intermediate positions and movable between retracted and dressing positions, a dressing compensator movable from a cocked position to a compensating position moving said grinding wheel spindle toward said diamond a predetermined dress compensating distance, first program operating means for causing a first program of events including moving said dressing compensator to its compensating position, traversing the grinding wheel from its second intermediate position to its first intermediate position, and moving the diamond from its retracted to its dressing position, second program operating means for carrying out a second program of events including moving said diamond to its retracted position, cocking said dressing compensator, and reversing said wheel traverse direction from the first intermediate position toward the second intermediate position, a limit switch movable from a first position when the grinding wheel is on either side of its intermediate positions to a second position when the grinding wheel is between its intermediate positions, means responsive to movement of said limit switch from its first to its second position upon movement of said grinding wheel from its first extreme position past said first intermediate position for enabling operation of said first program operating means, means responsive to movement of said limit switch to its first position as said grinding Wheel reaches said second intermediate position from said first intermediate position for initiating actuation of said first program operating means, means responsive to movement of said limit switch to its second position as said grinding wheel reerses its traverse direction for enabling said second program operating means, and means responsive to arrival of said grinding wheel at said first intermediate position for initiating actuation of said second program. operating means.

17. The combination according to claim 16, iurther provided with means including a dress finish sensing switch responsive to arrival of said grinding wheel axis at a predetermined distance from the diamond dressing position and subsequent movement of said grinding Wheel from said second to said first intermediate position for disenabling said means for enabling said first program operating means.

18. The combination according to claim 17, further provided with third program operating means for carrying out a third program including cocking of said dressing compensator, movement of said grinding wheel from its first intermediate position to said second extreme position, feed movement of the grinding wheel into the bore surface until the grinding wheel axis is a predetermined distance from the diamond dressing position, back ofi? movement of the grinding wheel, dress compensating feed movement of the compensator, traverse of the grinding wheel toward said second intermediate position, movement of the diamond to its dressing position, and dressing traverse 7 11 of the grinding wheel to its first intermediate position, and means responsive to actuation of said dress finish sensing switch and subsequent movement of said grinding wheel from its second to its first intermediate position to initiate actuation of said third pro-gram operating means.

19. The combination according to claim 18, further provided with means responsive to completion of the events of said third program for re-initiating actuation of said third program operating means.

20. In a method for diamond dressing a new grinding wheel preparatory to grinding an internal workpiece surface to a predetermined size, the steps of providing a dressing position for the diamond which is a predetermined distance from the final internal surface in a direction transverse to the spindle axis, dressing a new grinding wheel mounted on said spindle. by advancing the spindle toward the diamond in a direction transverse to the spindle axis to feed the wheel and then moving the diamond and wheel relativeto each other to dress the wheel, repeating the feeding and dressing steps until the spindle axis has advanced to within la first predetermined distance from the diamond measured in a direction transverse to the spindle axis and the wheel has thereafter been dressed without further feeding, traversing the grinding wheel into grinding position within the workpiece, feeding the grinding wheel and spindle toward the internal workpiece surface, and stopping the feed movement when the spindle axis has arrived at a second predetermined distance from said diamond. I

.21. In a method for diamond dressing a neW grinding wheel preparatory to grinding an internal workpiece surface to a predetermined size, the steps of providing a diamond dressing position which is a predetermined distance from the final internal workpiece surface measured in a direction transverse to the spindle axis, feeding a new spindle-mounted grinding wheel a predetermined dress compensating distance toward the diamond in a direction transverse to the spindle axis, moving the grinding wheel and diamond relative to each other to dress the wheel, again feeding the Wheel toward the diamond the same predetermined distance and moving the diamond and wheel relative to each other toagain dress the wheel, repeating the feeding and dressing steps until the spindle axis has advanced to a first determined distance from the diamond dressing position "and the wheel has then been dressed without further feeding of the wheel toward the diamond, traversing the wheel into the workpiece and feeding vthe wheel into the internal workpiece surface until the spindle axis is a second predetermined distance from the diamond dressing position.

22. The combination according to claim 21, further including the steps of backing off said wheel from the finished internal workpiece surface, feeding the wheel said predetermined dress compensating distance toward the diamond to compensate for wheel wear, moving the wheel and diamond relative to each other to again dress the '12 wheel, replacing the finished workpiece with an unfinished workpiece, causing the wheel to enter the new workpiece, and feeding the wheel intothe internal workpiece surface of the new workpiece until said spindle reaches a third predetermined distance from said diamond dressing position.

23. In combination with an internal grinding wheel spindle having a traverse slide and cross slide, a diamond movable in a direction transverse to the spindle axis between retracted and dressing positions, a workpiece station at one side of said diamond, the diamond dressing position being a predetermined distance from the final internal workpiece surface in a direction transverse to the spindle axis, means for repeatedly and sequentially feeding the grinding wheel spindle toward the diamond and moving the grinding'wheel and diamond relative to each other to dress the wheel, means for sensing the arrival of the spindle axis at a first predetermined distance from the diamond dressing position, and grinding cycle initiating means responsive to actuation of said sensing means to terminate said repeated feed, traverse, and dressing movements. 1

24. The combination according to claim 23, said sensing means being iactuatable by final feeding movement of said grinding wheel spindle toward the diamond but before said final dressing movement, and means forcausing said grinding cycle initiating means to be ineffective until said final dressing movement has been completed.

25. The combination according to claim 23, said grind- .ing cycle initiating means including means for causing the grinding wheel to traverse into the workpiece, means responsive to arrival of the grinding wheel in the workpiece for feeding the grinding wheel into the internal workpiece surface, and means responsive to the arrival of the spindle axis at a second predetermined axis from said diamond dressing position for halting said feed movement.

26. In combination with an internal grinding wheel spindle having a traverse slide and cross slide, a diamond movable in a direction transverse to the spindle axis between retracted. and dressing positions, a workpiece station at one side of said diamond, the diamond dressing position being a predetermined distance from the final internal workpiece surface in a direction transverse to the spindle axis, means for repeatedly and sequentially feeding the grindingwheel spindle toward the diamond and moving the grinding wheel and diamond relative to each other to dress the wheel, means for sensing the arrival of the spindle axis .at a first predetermined distance from the diamond dressing position, and grinding cycle initiating means responsive to actuation of said sensing means and a subsequent dressing movement of said wheel and diamond to terminate said repeated feed, traverse, and dressing movements.

N 0 references cited. 

1. IN A METHOD FOR DIAMOND DRESSING A NEW GRINDING WHEEL PREPARATORY TO GRINDING A WORKPIECE BORE TO A PREDETERMINED DIAMETER, THE STEPS OF PROVIDING A DRESSING POSITION FOR THE DIAMOND WHICH IS A PREDETERMINED DISTANCE FROM THE FINAL BORE DIAMETER IN A DIRECTION TRANSVERSE TO THE SPINDLE AXIS, DRESSING A NEW GRINDING WHEEL MOUNTED ON SAID SPINDLE BY ADVANCING THE SPINDLE TOWARD THE DIAMOND AND TRAVERSING THE WHEEL PAST THE DIAMOND IN THE DIRECTION OF THE SPINDLE AXIS, REPEATING THE DRESSING STEPS UNTIL THE SPINDLE AXIS HAS ADVANCED TO WITHIN A FIRST 